Add arrow to message bubbles and improve spacing (#2474)

Add arrow to message bubbles and improve spacing (#2474)

* Add arrow to message bubbles and improve spacing

* make bubble message avatar smaller

* add bubble layout for event content

* adjust bubble arrow

* fix missing return statement for event content

* hide bubble for event content

* add new arrow to bubble message

* fix avatar username relative alignment

* fix types

* fix code block header background

* revert avatar size and make arrow less sharp

* show event messages timestamp to right when bubble is hidden

* fix avatar base css

* move message header outside bubble

* fix event time appears on left in hidden bubles